PAMCO or points?

[jd750ace]

Try the other plug wire, and make sure your induction clamp is as close to the spark plug as you can get it. The induction clamp IS directional on many lights, so make sure it's turned the right way. If it's un-marked, try turning it around.

 

[XSsesive50]

Try the other plug wire, and make sure your induction clamp is as close to the spark plug as you can get it. The induction clamp IS directional on many lights, so make sure it's turned the right way. If it's un-marked, try turning it around.

Sounds like a good idea.

Any recommendations on spark plugs for the PAMCO system or stay with stock?

 

[XSsesive50]

Also, there are 2 red and white wires coming from the battery. The installation only says hook up to "the" red and white wire. Do I connect the PAMCO to one or splice into both?

 

[5twins]

Those two R/W wires that originally fed your two old coils "Y" off the same wire in the harness so you can use either one. I used one for my new coil and the other for the Pamco. I put a 7.5 amp fuse on the one going to the coil, as per Pete's recommendation.

 

[jd750ace]

Sounds like a good idea.

Any recommendations on spark plugs for the PAMCO system or stay with stock?

Stock if you use 5K resistor caps, or run straight caps, and resistor type plugs. One or the other, but not both.
I have BPR7ES resistor plugs and the caps that came with my Dyna coil with 7mm standard wire stock from NAPA.

 

[XSsesive50]

I went with NGK BPR7EIX Iridium Spark Plugs and she runs great.......on 1 1/2 cylinders. The right cylinder just isn't firing like it should. I have come to the conclusion that the right cylinder may need new piston rings. There is just not enough exhaust pressure even with a new ignition system. Could the exhaust valve be carboned up bad enough to cause this?

 

[retiredgentleman]

I went with NGK BPR7EIX Iridium Spark Plugs and she runs great.......on 1 1/2 cylinders. The right cylinder just isn't firing like it should. I have come to the conclusion that the right cylinder may need new piston rings. There is just not enough exhaust pressure even with a new ignition system. Could the exhaust valve be carboned up bad enough to cause this?

I see you previously said you had only 120 psig with the compression test. Have you done a more recent compression test? If both cylinders have 120, I don't think the right cylinder lack of firing can be blamed on compression, while the left cylinder fires OK.

With 120 psig compression, your engine is worn internally, and is never going to run well, until you do a top-end re-build.

A Pamco ignition was good thing to do. Using expensive iridium plugs, on an engine that has internal wear problems, seems like a waste of money to me.

 

[yamahammer]

It might not be an ignition problem either. Fuel and spark trouble masquerade as each other pretty interchangeably. A vaccum leak or improper pilot screw position. There are a few threads on here about dead cylinder syncing your engine, might give that a try.

 

[XSsesive50]

If it's not the rings, I don't know what else would cause such weak exhaust pressure.

 

[XSsesive50]

It might not be an ignition problem either. Fuel and spark trouble masquerade as each other pretty interchangeably. A vaccum leak or improper pilot screw position. There are a few threads on here about dead cylinder syncing your engine, might give that a try.

I disassembled the carbs and cleaned them, including removing all jets and cleaning. No obvious damage or problems with them. Removed gas tank and petcocks, no issues.

 

[XSsesive50]

Update: Yesterday I disassembled the carbs just to make sure I didnt miss anything and I noticed while looking into the throttle body that the butterflys werent even when closed. The right side, which is the side I had weak exhaust on, wasnt open as much as the left. I adjusted the butterfly with the synch screw until they both appeared even and reinstalled. The bike started but ran quite high at idle, which I lowered and she smoothed out nicely. Both exhausts now sound equal with equal pressure. I attribute the high idle to basically running on the left cylinder. I hope I didnt do any damage with the 14 miles or so in test rides on 1 cylinder trying to diagnose this.

 

[XSsesive50]

I took a short ride this morning and the bike runs great. I also switched to Uni Air filters after reading about better (smoother) air flow and that the pod filters may cause turbulence and rough running. I am very pleased with the Uni's. Oh and the high idle was due to the throttle cable being pinched under the gas tank and causing it not to allow the carb to snap back down to proper idle. Thanks for all of the input.

 

[TwoJugs]

Motor is probably fine. Takes more then that to hurt an XS. Don't be over concerned about the comp test numbers, as long as they are even and not real low, under 100. Your crank speed, throttle position and gage itself will vary the outcome. I too found similar issues with a few bikes. Carb sync is one of those first things to set once running, after with timing, valve clearance and cam chain is all done. Get a set of vacuum gages or build your own manometer. I find the gages to work fine, spend a few $ and save time. Or go the other way if that is your situation.

 

[5twins]

I told you to sync your carbs on page one in post #4. They work better that way, don't they, lol.

 

[XSsesive50]

I told you to sync your carbs on page one in post #4. They work better that way, don't they, lol.

You did indeed say that and the fact is I was being lazy and didn't want to go to the trouble of removing the carbs again. I also didn't know about the synch screw on the carbs. Which makes synching very easy. Thanks for the help. The bike is running great and after I installed my Moto Lanna seat yesterday (that was the last part of my project) I took her for a ride to the local Yamaha shop and showed her off. The 30 years experience tech there was impressed as well as the young kid working parts. The bike is older than he is. Lol.

 

[XSsesive50]

Pics of my 1978 XS650.

 

[pregrid]

Sweet bike. Don't you just love this place?

 

[XSsesive50]

Sweet bike. Don't you just love this place?

Thank you. I am new to the XS650 world and love the limitless possibility's with these bikes.